Country profile: Belgium

In the fourth of our country profiles, EDENext caught up with Guy Hendrickx, from Avia-GIS in Belgium, and his Belgian colleagues to find out more about the vector-borne disease situation in their country and the role their institutes will be playing in EDENext.

1. What vector-based disease challenges does Belgium face?

In Belgium the established vector-borne diseases with the highest public health impact are Lyme borreliosis transmitted by the tick Ixodes ricinus and Puumala virus transmitted through rodent urine. A recent detailed area-wide survey of mosquito diversity has revealed the presence of many potential West Nile mosquito vectors and of two overwintering (but not spreading) invasive mosquito species: Aedes japonicus and Ae koreicus (first ever recording outside Asia). Aedes albopictus was recorded in Belgium in 2001, but is now absent. From a veterinary perspective, the main challenge of the past few years was the explosive introduction, establishment and spread of bluetongue (BTV8) in 2006. This ruminant disease is transmitted by a variety of local Culicoides biting midges. Global change opens new areas to species previously limited in their expansion by geographical or climatic barriers. Belgium, as is the case for many European countries, is hence facing new problems related to emerging vector-borne diseases and invasive species. This is not only limited to public and veterinary health but also includes agricultural insect pests such as the leafminer Cameraria ohridella and the oak processionary moth Thaumetopoea processionea.

2. What are your institutes doing to tackle this?

Four Belgian Institutes participate to EDENext and cover all the main issues related to VBD risk in Belgium:

The Evolutionary Ecology Group at the University of Antwerp (P30) studies population ecological and behavioural ecological questions in a number of mostly terrestrial vertebrate model systems (rodents, songbirds). Very often, the fundamental questions are set in an applied framework, focusing on animals that are a pest in agriculture, a reservoir for infections or key species in nature conservation. The group has teaching responsibilities at different levels, a strong research record and a drive to make its scientific knowledge available to society. The team has long-term experience in studying the epidemiology of rodent-borne infections including European hanta-viruses, African arena-viruses, bubonic plague, leptospirosis and echinococcosis. The main question of interest is the link between the ecology of the host (spatial, temporal) and the epidemiology of infections in the host as well as the risk for humans to become infected. The team combines active field work in Europe, Africa and Central Asia, with experimental work in the lab and the use of mathematical modelling as a tool for hypothesis generating and for simulations. Also long-term experience in ecological research of birds and related tick population dynamics in Belgium have been developed over the last decade.

Trapping rodents (photos by Evolutionary Ecology Group, UA)

Above: Forest trapping site in Chimay

Above: Land cover map of trapping site

Above: Positioned Sherman trap

Above: Captured bank vole (Myodes glareolus)

The Medical Geography Research Group at UCL (P44) uses techniques drawn from geography such as remote sensing, GIS and various tools of spatial analyses to investigate and model the complex web of landscape factors influencing the distribution of diseases. The spatial distribution of vector-borne and zoonotic diseases is related to a complex constellation of factors, of which important ones are land cover and land use at the landscape scale. The landscape provides not only habitat and various resources for vectors and hosts, but it also is the place of human activities. Through its activities, man shapes the landscape, and enhances contact with infected vectors or pathogens. An interesting and concerning illustration of this are tick-borne diseases. Landscape management and wildlife management can influence the abundance of ticks and infected ticks, but can also influence to what extent we are exposed to infected ticks. Our previous research experience covers various aspects of mosquito, tick, sand fly and rodent-borne diseases, both in temperate and tropical areas.

Trapping ticks (photos by Medical Geography Research Group, UCL)

Above: Tick trapping site in Forêt de Soignes/Zonn, a forest heavily used recreationally on the periphery of Brussels (photo by Sen Li)

The research conducted by the LUBIES Group at ULB (P45) deals with demographic and spatial changes in several harmful organisms, with a special focus on the factors favouring their spread and persistence, that we analyse and model using spatially-explicit and spatially-realistic population models and simulations. We have been contributing to a better understanding of the spatial epidemiology of several emerging diseases such as avian influenza, bovine tuberculosis and bluetongue.

Avia-GIS (jointly with ERGO, a partner of EDENext as Euro-AEGIS, P46) is an SME specialised in the development of spatial information systems for disease management and decision support. It gained its experience working on the spatial modelling of the various live cycle components of animal trypanosomiasis in West Africa and now applies these techniques on a variety of vectors in Europe. Our main research topics are: the development of spatial distribution models for disease vectors, pathogens and hosts; the development of cost-effective spatial sampling strategies; the issue of false-negative trap results; the assessment of spatial uncertainty in model outputs; and the development of wind dispersal models. Recent relevant project highlights include:

Avia-GIS has been a driving force in establishing and running the EDEN consortium (FP6)

Coordination of VBORNET, the European Network for Arthropod Vector Surveillance for Human Public Health (ECDC, Stockholm, Sweden)

Coordination of VECMAP (ESA, Noordwijk, Netherlands) which aims at developing a software suite to map and model disease vector distributions

Partner of MODIRISK (Belspo, Brussels, Belgium) which aimed at mapping and modelling mosquito species at a 1km resolution in Belgium and the Netherlands

Coordination of TigerMaps (ECDC, Stockholm, Sweden) which included a multi-model approach as a first attempt to model and predict the spread of Ae albopictus in Europe.

Predicting the spread of Culicoides by wind

Above: Culicoides trapping in BTV8 infected herd in primary spread area during the 2006 outbreak (photo by Guy Hendrickx)

Above: Land cover map of area of primary spread of BTV8 in 2008 in Belgium

Each of the four Belgian partners involved with EDENext has a specific role:

The Evolutionary Ecology Group at the University of Antwerp (P30) is a member of the rodent group and focuses on the identification of the causal drivers of the changes in PUUV (Puumala virus) epidemiology using an interdisciplinary approach by combining research on bank vole-PUUV ecology/evolution with landscape/climate patterns and human epidemiological NE data. In practice, rodent sampling, PUUV diagnostics, statistical and theoretical modelling are carried out by the researchers involved. Prof Dr Herwig Leirs, principal investigator, is a rodent ecologist with a long experience in the study of rodent population ecology and the ecology of rodent-borne infections. Dr Katrien Tersago is a post-doc ecologist who finalised her PhD project, as part of EDEN, on the eco-epidemiology of PUUV in Belgium. Dr Jonas Reyniers is a post-doc physicist (with experience in modelling biological systems) who recently joined the team with the aim of reinforcing the mathematical modelling expertise in the team. In addition a number of PhD students will be studying bank vole-PUUV transmission dynamics and evolution, including Benny Borremans and Sanne Helsen.

The Medical Geography Research Group at UCL (P44) collaborates as a member of the horizontal modelling group with EDENext vector teams to investigate relationships between land cover, land use, vector habitat and host interactions and the landscape scale. The objective is to bring further the integration of spatial empirical-statistical approaches and epidemiological modelling. Both approaches can contribute to further understand disease ecology and disease transmission by mobilizing either various types of empirical data, or by reconstructing specific processes involved in the system. The team is led by Prof Sophie Vanwambeke and also includes Dr Nienke Hartemink and Caroline Zeimes.

The research conducted by the LUBIES Group at ULB (P45) is a member of the horizontal modelling group and investigates how statistical modelling methods could be improved to retrospectively analyse space-time data on invasive vectors and diseases. The approach will be based on a set of simulated invasions scenarios with known life-history parameters (growth rate, dispersal rate, etc.). These simulated invasions will then be sampled and subject to statistical analysis to identify which statistical method can help to quantify those parameters. In addition, we are keen to collaborate with other EDENext partners to contribute on demand whenever our expertise on spread modelling is required. This research will be carried out as part of the post-doc project of Aiko Gryspeirt under the supervision of Marius Gilbert

Avia-GIS together with ERGO (jointly partner of EDENext as Euro-AEGIS, P46) is in charge of the data management group which has two main activities: (a) a service component providing assistance and training to all EDENext partners regarding spatial data required for the development of spatial epidemiological models at various scales (ERGO) and (b) a research component to develop pan-European Union host distribution and diversity models and develop improved wind spread models for Culicoides midge-borne diseases (Avia-GIS). ERGO is from Oxford in the UK and details of its contributing staff will be available in due course in the UK country profile. The Avia-GIS group is led by Dr Guy Hendrickx and Dr Els Ducheyne, respectively senior specialists in spatial epidemiology and spatial modelling. Research on wind spread models will be conducted as part of the PhD project of Sarah Van Steenwinkel. Technical assistance will be provided by Bart de Groot (ICT) and Els Goossens (Distance Learning).